Mining is one of the most hazardous jobs. There are few reliable figures but unions estimate that around 10 million people dig for a living and 12,000 may die every year from roof falls, explosions, fires, flooding and other underground and surface accidents.

There is even less reliable data on the injuries incurred by miners but tens of thousands of people have their health damaged every year from conditions such as pneumoconiosis, hearing loss and the effects of vibration, says the Geneva-based global union IndustriALL, which represents 50 million workers in 140 countries in the mining and energy sectors.

Most fatal mining accidents now occur in the "informal" sector, where poor people, mainly in developing countries, dig for gold or other minerals with few resources. Their deaths and injuries are seldom recorded, says the UN's International Labour Organisation.

"Worldwide, there are fewer accidents now in the formal sector than there were 10 years ago, but some countries still do not systematically record and report their performance. At the same time, the informal mining sector is still rife with accidents and health hazards", said Martin Hahn, ILO mining specialist.

China, which mines one third of the world's coal and employs nearly half the world's miners, has the worst record for accidents. According to the central government, 1,049 Chinese died in mine accidents in 2013, a 24% decrease on 2012 and a fraction of the 7,000 or more who died in 2003. However, human rights groups caution that the latest figures may be significantly higher due to under-reporting by unregulated mining companies.

Most of the major accidents in recent years have been in private as opposed to state mines. At least 104 people died in 2009 in an accident in Heilongjiang; an explosion killed 45 people at the Xiaojiawan coal mine in Sichuan province and a few days later 14 miners were killedin Jiangxi province. Last year, a landslide trapped 83 people in the Gyama mine in Tibet.

Turkey is renowned for its coal mining accidents, says IndustriALL. "In 73 years more than 3,000 miners have been killed in Turkey. Every death in a mine is avoidable," said IndustriAll. In 1992, 270 men died in an accident Zonguldak province.

But research from China, India and Europe suggests that mining is indirectly responsible for hundreds of thousands of premature deaths every year.

"Hundreds of thousands of lives could be saved, and millions of asthma attacks, heart attacks, hospitalisations, lost workdays and associated costs to society could be avoided, with the use of cleaner fuels, [and] stricter emission standards and the installation and use of the technologies required to achieve substantial reductions in these pollutants," said the report.